The present invention relates to doors which are to be prevented from opening in the event of a fire.
Many types of building structures have doorways whose doors are to be maintained permanently closed in the event of a fire, either to comply with local fire codes or, even if not required by fire codes, for safety reasons. It is desired to provide this capability, for example, for doors which are supported by aluminum geared hinges, which may be continuous hinges. It is recognized that it would be desirable to provide this capability with inexpensive, easily installed components which are unobtrusive. There may also be situations where it is desirable to achieve fire ratings by retrofitting existing doors in a simple and inexpensive manner.
In order for a door to be fire rated, it must be equipped with components which will completely prevent the door from being opened, other than by destroying it, when the door is heated to above a predetermined temperature characteristic of the temperature existing when a fire occurs.
It is already known in the art to employ thermally intumescent materials for sealing doors in a closed position in response to the heat generated by a fire. However, in known installations, application of the intumescent sealing materials is difficult and time consuming.